In light-emitting diode (LED) devices, an organic material such as a resin has been conventionally used as a sealing material for sealing and coating an LED element and a substrate which supports the LED element. However, the sealing material made of a resin tends to deteriorate due to heat generated by driving devices, light and/or moisture in the environment, and the life span of such a sealing material is short. Thus, a stable substitute material for the sealing material made of a resin has been desired.
As such a substitute material which can solve the above problem and is stable against heat, light and/or moisture in the environment, a sealing material made of glass is conceivable. However, in a case of conventional sealing materials made of glass, the temperature for sealing treatment at a level of 500° C. or higher is required due to the restriction of the glass softening points. The sealing treatment at such a high temperature is not preferred to members constituting LED devices from the viewpoint of reliability. Therefore, in order to use glass as a sealing material, glass which can be seal-treated at a sealing treatment temperature of lower than 500° C. is required.
Further, Patent Document 1 discloses P2O5—SnO glass for sealing a cathode-ray tube (CRT) wherein the sealing treatment temperature is from 400° C. to 430° C.    Patent Document 1: JP-A-7-69672